1. Field of Invention
The present invention relates to a thermosiphon, and in particular to a condenser for condensing a working fluid, in a thermosiphon.
2. Description of the Related Art
Heretofore, as a thermosiphon used for example in a refrigeration apparatus, one where a condenser is constructed by coiling a part of a pipe with a working fluid filled thereinside into a coil shape, and this condenser then covered over an outer periphery of the cold part of the refrigeration apparatus, is used. Furthermore, there is also known a thermosiphon of a construction where an inlet pipe and an outlet pipe for a working fluid are connected above and below a condenser constructed with a plurality of holes bored in parallel in a metal block so as to surround a cold part and then a working fluid is filled into the condenser, the inlet pipe and the outlet pipe. Moreover, in this thermosiphon, the holes are communicated with an inside bottom part of the condenser, the construction being such that the working fluid condensed in the holes accumulates at the inside bottom part of the condenser and flows out from an outlet portion to an outlet pipe connected to the bottom side of the condenser.
However, in the former configuration, if the apparatus using this thermosiphon is inclined, the condensed working fluid accumulates inside the condenser, so that there is the likelihood of a drop in the heat transport efficiency. Moreover, in the latter configuration also, if an apparatus using this thermosiphon is inclined, then depending on the incline direction, the position of the liquid portion can become higher than the inside bottom face of the condenser. If so, then as with the former configuration, the condensed working fluid accumulates inside the condenser so that there is the likelihood of a drop in heat transport efficiency. Furthermore, since a large number of holes must be bored in the metal block, there is a problem with increase in manufacturing cost.
It is an object of the present invention to solve the abovementioned problems by providing a thermosiphon of low cost and simple construction and having a condenser which can reliably discharge a condensed working fluid from an outlet pipe even if the apparatus is somewhat inclined.
A thermosiphon according to a first aspect of the present invention is one where in a thermosiphon comprising a condenser connected to a cold part of a refrigeration apparatus, and an inlet pipe and outlet pipe connected to the condenser and which can pass a working fluid thereinside, the condenser comprises; an attachment part attached to the cold part for conducting heat from the cold part, and a condensing part provided at an end of the attachment part for condensing the working fluid, and the condensing part has a cavity portion thereinside, and an inside bottom part of the cavity portion is formed descending towards an outlet hole communicating with an outlet pipe for the working fluid.
By having the above construction for the present invention, when the working fluid in a vapor state which has flowed to the condensing part from the inlet pipe loses heat in the cavity portion inside the condensing part and is liquefied, it accumulates at the inside bottom part of the cavity portion and flows out from the outlet hole communicated with the outlet pipe. At this time, since the inside bottom part of the cavity portion is formed descending towards the outlet hole which is communicated with the outlet pipe of the working fluid, then even if the condenser is somewhat inclined, if this incline is less than the slope of the inside bottom part of the cavity portion which descends towards the outlet pipe, the working fluid does not accumulate in the condensing part, and flows along the inside bottom part of the cavity portion and flows out from the outlet hole to the outlet pipe. Hence there is no drop in heat transport efficiency.
Furthermore, a thermosiphon of a second aspect of the invention is one where in the first aspect of the invention, the condensing part is constructed with a heat exchange member attached to the cavity portion. By constructing the present invention in the above manner, the condensing part can be easily constructed by attaching a separately formed heat exchange member to inside the concavity portion.
A thermosiphon of a third aspect of the invention is one where in the second aspect of the invention, the heat exchange member is constructed from a plate-like base, and a heat exchange part provided upright on the base, the construction being such that the cavity portion is sealed by the base. By constructing the present invention in the above manner, the heat exchange part of the heat exchange member can be inserted into the cavity portion formed in the condensing part, and also the opening of the cavity portion can be sealed by the plate-like base of the heat exchange member. Therefore the sealing of the cavity portion and the attachment of the heat exchange member can be performed simultaneously. Hence assembly of the condensing part becomes even easier.
Furthermore, a thermosiphon of a fourth aspect of the invention is one where in any one of the first through third aspects of the invention, the inside bottom part of the cavity portion is formed descending so as to incline more than 10 degrees with respect to the horizontal direction when the condenser is connected to the cold part of the refrigeration apparatus. By constructing the present invention in the above manner, then with a refrigerator or the like incorporating the refrigeration apparatus and which is specified for example by law so that at least this will not fall over if inclined at 10 degrees, since the inside bottom part is inclined at more than 10 degrees to the horizontal direction, then even if it is inclined within the specified range, the working fluid will not accumulate in the condensing part, and will flow down along the inside bottom part of the cavity portion and flow out from the outlet hole to the outlet pipe.